Method for breeding highly lactiferous cows by using rumen-protective amino acids

ABSTRACT

Lysine and methionine which are limiting amino acids of dairy cows are administered to dairy cows to decrease the BUN value that has an adverse effect on the conception rate and to increase the blood glucose required to improve the energy balance, that alanine and glutamine are administered to dairy cows to increase the blood glucose and to improve the liver function, and that the use of these amino acids is effective for keeping good conditions of dairy cows, allowing earlier arrival of initial estrus without any stress, improving the mating conception rate and decreasing the non-conception rate.

TECHNICAL FIELD

The present invention relates to a nutrient feed for expediting breedingof high-level lactation dairy cows and a method of breeding dairy cowsby feeding them with the nutrient feed.

TECHNICAL BACKGROUND

Dairy cows rapidly increase amounts of their milk from immediately aftercalving to the prior period of lactation to recover their bodilystrength in the puerperal period. Accordingly, the energy consumption ofdairy cows reaches the maximum, and the nutrition demand isphysiologically increased. Despite this, even normal healthy dairy cowsreduce the appetite owing to their puerperium, and the feed intake istemporarily reduced. Consequently, although the energy and the nutrientare not sufficiently supplemented, the energy consumption is great, sothat the energy balance becomes minus and the insufficient nutritionoccurs. As a result, dairy cows naturally try to supply the energy uponusing all of their body fats. Unless the metabolism in the body proceedssmoothly, ketosis or an abomasum displacement occurs. The energy is usedpreferentially in the order of body maintenance, lactation and breeding.When the energy balance is in the minus condition, it causes thedecrease in the body weight of dairy cows, diseases and environmentalstress, as well as the delay of the first estrus of dairy cows and theovary function disorder thereof, influencing the breeding results(Mizomoto K., Dairy Japan, February 1993, extra edition).

Yasuho states that ruminants tend to suffer from abnormal metabolism ofsugar and lipid, such as ketosis at the peak stage of lactation or atthe final stage of conception (New Chemistry of Dairy Cows, Noson GyosonBunka Kyokai, published Jul. 15, 1987). He further states by citingKrebs (1996) that when glyconeogenesis increases in the liver, theformation of ketones increases.

In the diabetic complication that risks the life, ketones(D-3-hydroxybutyric acid, acetoacetic acid and acetone) are formed, andproton at a high concentration that exceeds an acid-base buffer systemof the body is formed, resulting in the dangerous decrease in the pH ofthe blood. Although ketones have been considered to be metabolic wastes,it is currently known that ketones are used as a fuel in addition toordinary fuel glucose of the brain in the fasting. The controlledformation of ketones induces ketosis. In the ketosis, the pH of theblood remains buffered in the normal range. This is quite an importantglucose saving to the fasting. Since the brain cannot use fatty acid asa fuel, glycogen stored comes to be exhausted (“Easy Metabolism, BasicKnowledge of Nutrient Metabolism” translated by Aso Y.).

G. D. Baird (J. Dairy Sci. (65) 1-10, 1982) states that the increase inthe concentration of ketones in the blood has an adverse effect onbreeding of dairy cows.

Baalsrud (Nils-Ivar Baalsrud, U.S. Pat. No. 3,959,496) discloses thatbefore or after calving of dairy cows, the actual amount of milk is notbalanced with the amount of milk produced from the energy inherent indairy cows and the actual amount of milk is increased from 1 monthbefore calving to 5 months after calving, with the result that theenergy balance of dairy cows is lost during this period, the consumptionis increased and the overall energy balance is minus. It is furtherstated that a rumen-bypassed biologically active substance and glucoseare administered to improve this.

Kato discloses that since excess intake of proteins in dairy cows in thepeak period of lactation deprives the energy of dairy cows, the energyloss of dairy cows greatly influences the breeding, that a proteindecomposed in a rumen becomes ammonia and is used by bacteria in therumen but excess ammonia is detoxicated into urea in the liver whichincreases blood urea nitrogen (BUN), and that when the BUN valueincreases, a sperm, an egg and a fetus (embryo) are seriously influencedand killed (Kato H., Dairy Japan, February 1993, extra edition).

Butler studied a relationship between the BUN value and the conceptionrate in the first estrous period after 60 days from calving, andreported that the conception rate is 53% at the blood concentration of19 mg/dl or less, whereas it is decreased to 35% at the bloodconcentration of more than 19 mg/dl (W. R. Butler et al., J. Anim. Sci.1996, 74: 858-865).

Meijeijer measured a concentration of a free amino acid in the plasmaand the muscle of high-level lactation dairy cows to which aconcentrated feed, a corn silage and a predried hay silage wereadministered from 2 weeks before calving to 15 weeks after calving. As aresult, it was found that the concentrations of methionine,phenylalanine, glutamic acid and glutamine in the plasma during theperiod of from 6 to 15 weeks after calving were reduced by from 16 to25% as compared with those before calving. The change in the amino acidconcentration in the muscle from the later stage of conception to theinitial stage of lactation suggested that the protein in the muscle isdecomposed because amino acids are supplied to a mammary gland. It isfurther stated that in the high-level lactation dairy cows, glutaminelatently controls the synthesis of a milk protein [G. A. L. Meijeijer etal., J. Dairy Sci., 78, (S), 1131 (1995)].

Torii [Japanese Laid-Open (Kokai) No. 54,320/1988] discloses apharmaceutical composition which is composed mainly of alanine andglutamine and which is effective for treating anti-alcoholic diseases.Mawatari [Japanese Laid-Open (Kokai) No. 229,940/1993] discloseshepatocyte regeneration accelerating agent which contains alanine orglutamine as an essential ingredient and which can increase hepatocytesto accelerate regeneration of the liver. Mawatari [Japanese Laid-Open(Kokai) No. 221,858/1993] discloses that a hepatitis treating agentcontaining at least one of alanine, glutamine and ornithine is effectivefor treating viral hepatitis, drug-induced hepatitis and fulminanthepatitis. Suda [Japanese Laid-Open (Kokai) No. 50,917/1986] disclosesan anti-alcoholic liver disorder-treating composition containing alanineand ornithine as active ingredients.

The present invention is to develop a nutrient feed for expeditingbreeding of dairy cows and a method of expediting breeding of dairy cowsby feeding them with the nutrient feed.

DISCLOSURE OF THE INVENTION

The present inventors have found that lysine and methionine which arelimiting amino acids of dairy cows are administered to dairy cows todecrease the BUN value that has an adverse effect on the conception rateand to increase the blood glucose required to improve the energybalance, that alanine and glutamine are administered to dairy cows toincrease the blood glucose and to improve the liver function, and thatthe use of these amino acids is effective for keeping good conditions ofdairy cows, allowing earlier arrival of initial estrus without anystress, improving the mating conception rate and decreasing thenon-conception rate. These findings have led to the completion of thepresent invention.

That is, the present invention relates to a dairy cow feed or a cornsilage basic formula feed containing rumen-bypassed lysine (1) andglutamine and/or alanine (2) as essential ingredients and optionallycontaining methionine (3), and a method of breeding high-level lactationdairy cows, characterized in that a corn silage basic formula feedcontaining rumen-bypassed lysine (1) and glutamine and/or alanine (2) asessential ingredients and optionally methionine (3) is continuouslyadministered to high-level lactation dairy cows from 21 days beforecalving, preferably from 3 days before calving to 84 days after calvingsuch that the energy balance of high-level lactation dairy cows isalways plus and at least the amino acid demand of high-level lactationdairy cows is satisfied.

In order that dairy cows lactate, raise embryos and maintain their ownlife, it is necessary to consider the minimum protein balance and energybalance. The protein balance is determined from the amount of protein(DP) required by dairy cows, the amount of protein (IP) fed to dairycows by feed intake and through protozoa in a rumen and the amount ofprotein (RP) lost by scarves, urine, fecal matters and protozoa in arumen. When these amounts are in the order of IP−RP>DP, the amounts ofproteins of dairy cows are satisfied. However, when the amounts ofproteins are considered in more detail from the standpoint of aminoacids constituting proteins, the amino acid balance in the bodies ofdairy cows is inconsistent with ratios of amino acids in proteins ofdairy cows, and there are amino acids (limiting amino acids) in amountswhich do not reach those required to constitute proteins. When theseamino acids are supplied, the balance of amino acids required toconstitute proteins is given as a whole, and proteins are effectivelyused. Thus, there is no amino acid loss.

Meanwhile, unless limiting amino acids are supplied, the synthesis ofproteins in the bodies of dairy cows is restricted to the level oflimiting amino acids. Since amino acids other than limiting amino acidswhich do not constitute proteins are not used as proteins, theseproteins are, in many cases, metabolized or exhausted outside bodiesthrough various routes. During this metabolism, the increase in the BUNvalue of the blood is observed, and it shows a great burden on the liverfunction of dairy cows. Further, the increase in the BUN value of theblood has an adverse effect on the conception rate of dairy cows, andgives various influences such as the decrease in the bodily strength ofdairy cows, the delay of recovery thereof and the like.

Accordingly, all of amino acids effectively function to form proteinswithin dairy cows by supplying limiting amino acids to the level ofamino acids constituting proteins. As a result, the presence of extraamino acids that do not constitute proteins come to be extremelysuppressed. Therefore, ideally, until amino acids which dairy cows haveto exhaust outside their bodies through metabolism disappear, the BUNvalue of the blood derived from these amino acids is not increased, noris a burden exerted on the liver function ot dairy cows.

However, the body conditions of dairy cows are actually not constant,but always changed.

The BUN value of the blood cannot be reduced to zero because of theirregularity of feed ingredients, the change in the feed intake, thechange in digestion and absorption of feed, and the ability of dairycows themselves to synthesize proteins. Further, when the BUN value ofthe blood is high, the burden of the liver is increased owing to excessintake of proteins, imbalance of amino acids and the like. Accordingly,it is important that the liver function of dairy cows is always keptgood and dairy cows are controlled not to undergo the liver functiondisorder. The present inventors have found that alanine and/or glutamineis effective for improving the liver function of dairy cows. Theadministration of alanine and/or glutamine helps to keep good the liverfunction and the health conditions of dairy cows.

The types of limiting amino acids and the insufficient amounts thereofcan be determined upon calculating necessary amounts of amino acids of aruminant and amounts of amino acids given from a feed. In thiscalculation, a Cornell model on a carbohydrate and a protein system fordetermination of a feed of dairy cows is known (Search: AgricultureIthaca, NY: Cornell Univ. Agr. Exp. No. 34, 128 pp. 1990, ISSN0362-2754, cited herein as a reference data). This is proposed, as amodel for estimation of an amino acid demand or a feed of dairy cows andfor calculation of various changes with respect to adjustment ofnecessary amounts of nutrients of dairy cows which are changed over thecourse of time, formulation of a feed based thereon, control ofproliferation of dairy cows, control of breeding, environmentalinfluence through inhibition of excreta of dairy cows and the like. Thismodel is applicable to a computer spread sheet, and can be used in bothbeef cattle and dairy cows in different levels and different productiontypes. The Cornell model makes it possible to calculate metabolicproteins of dairy cows based on the type, the body weight in birth, theoverall body weight and the like under specific conditions of individualdairy cows (namely, whether dairy cows are in the maintenance cycle orin the lactation period or in the breeding period). Further, in thismodel, it is considered that dairy cows are reactive with a feedsupplied on the basis of a feed composition, a digestion rate anddigestive proteins (digestive proteins which are not influenced by thefunction of the forestomach and proteins of bacteria digested).Metabolic proteins required by a specific ruminant are calculated inthis manner, and the amounts of these proteins are compared withcalculated amounts of metabolic proteins given from a feed supplied.When feeding digestive proteins in amounts less than those required forspecific dairy cows in consideration of the physiological condition andthe lactation period, a feed additive containing the above-mentionedrumen-bypassed amino acids of dairy cows comes to be supplied to anecessary level.

The amount of the feed additive of rumen-bypassed amino acids added tothe basic feed is calculated by replacing the amounts of digestiveproteins lacking in the feed with amounts of methionine and/or lysineprotected from the function of the forestomach. This replacement can beconducted by analyzing amino acids of digestive proteins (supplied fromthe feed) using the above-mentioned Cornell model proposed by Chalupa etal. (Cornell Conference for production of a feed in 1991, p. 44, citedherein as a reference data). A protein fraction of a feed which has beendecomposed in the first (rumen) through third (psalterium) stomachs ofdairy cows is first separated from a protein fraction which has not beendecomposed in the forestomachs, and the amounts of methionine and lysinerequired for lactation and maintenance which amounts are calculatedusing the Cornell model are totalled, making it possible to calculatethe amounts of methionine and lysine required for a specific ruminant.

The types of essential amino acids to dairy cows and the insufficientamounts thereof to dairy cows can be known in detail from theabove-mentioned analyses including computer models other than theabove-mentioned model. However, these amounts are calculated amounts,and might be sometimes inconsistent with actual amounts. For example,dairy cows consume their bodily strength in calving. Consequently, thebodily strength is decreased immediately after calving, and the feedintake is reduced by approximately 20% on the average. When dairy cowsare bred and the amount of their milk, the quality of milk and theirhealth conditions are observed, the ideal breeding procedure obtainedfrom the computer model is not actually shown. However, even in thisstate, the amount of milk is actually as expected, and the quality ofmilk is not extremely decreased. This means that dairy cows themselvestry instinctively to continuously produce a necessary amount of milkduring the lactation period. Consequently, dairy cows are under seriousbodily burden, experience various stresses and consume their bodilystrength. This influences the production of milk in the following years,and also causes the increase in the stress of dairy cows, the delay ofthe first estrus, the ovary function disorder and the decrease in theconception rate. As a result, the number in days of non-conception isincreased, and the economical loss is great to dairy farmers.

Alanine and glutamine are also important to dairy cows, though these arenot amino acids other than the essential amino acids to dairy cowsaccording to the above- mentioned computer model. These amino acidsincrease blood glucose which is a basic energy to dairy cows, and helpdairy cows eliminate the decrease in the bodily strength and the stressowing to calving, making it possible to maintain the good healthconditions.

The above-mentioned amino acids improve the liver function. Accordingly,even when dairy cows undergo a burden in the liver for some reasons, theintake of these amino acids can return the liver function to a normalstate.

Consequently, the combined use of lysine, methionine, alanine andglutamine can maintain the good conditions of dairy cows as a whole.Specifically, the BUN value of the blood is decreased, and the bloodglucose value is increased to maintain the liver function. When thedisorder of the liver occurs, it is eliminated. Therefore, when thepreferable conditions of maintaining the preferable health conditions ofdairy cows are satisfied as mentioned above, good results of breedingare given, and preferable economical effects to dairy farmers, such asearlier arrival of the first estrus, the decrease in the number ofmatings and the decrease in the non-conception rate can be broughtforth.

EXAMPLES

The present invention is illustrated specifically by referring to thefollowing Examples.

Production Example 1

Production Example of rumen-bypass amino acid:

L-lysine hydrochloride (325 g), 99.5 g of methionine, 250 g of alanine,250 g of glutamine, 172.5 g of talc, 2.5 g of sodiumcarboxymethylcellulose and 135 g of water were charged into a kneader,and kneaded. The mixture was formed into cylindrical granules using anextrusion-pulverizer having a screen with 1.5 mm φ openings. The shapeof the thus-obtained granules was adjusted using a device for formingspherical granules (Malmerizer, supplied by Fuji Paudal) to obtainnearly spherical granules. The resulting spherical granules weresubjected to fluidized drying to give cores containing L-lysinehydrochloride and having a diameter distribution of from 1 mm to 2.5 mm.

A protective substance containing 1.68 parts by weight of lipase A“Amano” 6 (made by Amano Seiyaku K.K.) was dissolved in 98.32 parts byweight of hardened tallow. The mixture in an amount of 35.8 parts byweight per 100 parts by weight of the cores screened to a diameter of1.5 mm on the average was coated on the cores. Then, 7.2 parts byweight, per 100 parts by weight of the cores, of hardened tallow whichhad been molten. The resulting coated particles were subjected to theabove-mentioned evaluation test. Consequently, the elution into a rumenwas 9%, and the corresponding elution into digestive organs was 76%.

Production Example 2

Production Example of rumen-bypass amino acid:

L-lysine hydrochloride (616 g), 196 g of methionine, 525 g of alanine,525 g of glutamine, 172.5 g of talc, 2.5 g of sodiumcarboxymethylcellulose and 135 g of water were charged into a kneader,and kneaded. The mixture was formed into cylindrical granules using anextrusion-pulverizer having a screen with 1.5 mm φ openings. The shapeof the thus-obtained granules was adjusted using a device for formingspherical granules (Malmerizer, supplied by Fuji Paudal) to obtainnearly spherical granules. The resulting spherical granules weresubjected to fluidized drying to give cores containing L-lysinehydrochloride and having a diameter distribution of from 1 mm to 2.5 mm.

A protective substance containing 1.68 parts by weight of lipase A“Amano” 6 (made by Amano Seiyaku K. K.) was dissolved in 98.32 parts byweight of hardened tallow. The mixture in an amount of 35.8 parts byweight per 100 parts by weight of the cores screened to a diameter of1.5 mm on the average was coated on the cores. Then, 7.2 parts byweight, per 100 parts by weight of the cores, of hardened tallow whichhad been molten were coated thereon. The resulting coated particles weresubjected to the above-mentioned evaluation test. Consequently, theelution into a lumen was 9%, and the corresponding elution intodigestive organs was 72%.

Example 1

Thirty Holstein secundipara dairy cows (amount of milk produced—10,000kg/head/year, scheduled intake of a feed calculated in terms of a drymatter—24 kg/day) were divided into two groups, namely 15 cows in aprotein supply area (positive control area) and 15 cows in arumen-bypass amino acid supply area (RPAA supply area). In the dryperiod before calving, the dry period formula feed shown in Table 1 wasadministered to dairy cows in the protein supply area from 3 weeksbefore calving to the calving day. In the RPAA supply area, the dryperiod formula feed shown in Table 1 was administered thereto from 3days before the scheduled calving day. Subsequently, in the lactationperiod, the lactation period formula feed shown in Table 2 wasadministered thereto. The amino acid balance of the rumen-bypass aminoacid (RPAA) supply feed in the dry period is shown in Table 3, the aminoacid balance of the protein supply feed in the dry period in Table 4,the amino acid balance of the lysine-methionine-deficient feed and therumen-bypass amino acid supply feed in the lactation period in Table 5,and the amino acid balance of the protein supply feed in the lactationperiod in Table 6 respectively. The rumen-bypass amino acid obtained inProduction Example 2 was administered to dairy cows in the RPAA supplyarea in amounts shown in Tables 1 and 2. With respect to the breedingrecords, the intake of the feed calculated in terms of a dry matter isshown in Table 7. The health conditions and the fatness of dairy cowswere visually estimated according to the 5-grade method, and the scoresare shown in Table 8. The blood was sampled from all of dairy cows inboth of the protein supply area and the RPAA supply area on Day 14before scheduled calving and on Day 14 and Day 56 after calving. Then,the blood glucose value and the blood urea nitrogen (BUN) value weremeasured. The results are shown in Table 9.

TABLE 1 Dry period formula feed Rumen-bypass amino acid supply feedProtein supply feed*¹ Amount Dairy cow intake Amount Dairy cow intake ofa dry (Lbs/day), of a dry (Lbs/day), matter calculated as mattercalculated as (%) a dry matter (%) a dry matter Soybean cake 0.73 0.181.43 0.38 Grass silage 36.70 10.00 40.00 10.00 By-pass fat 0.73 0.180.72 0.18 Corn fermen- 3.88 0.98 0.48 0.12 tation cake Corn 4.84 1.225.64 1.41 Barley 4.84 1.22 5.96 1.49 Vitamin• 0.83 0.21 0.71 0.18mineral Hay (oats) 36.70 10.00 40.00 10.00 High-water- 3.97 1.00 4.001.00 content corn By-pass amino 0.78 0.20 — — acid Meat meal with — —0.48 0.12 bone Blood meal — — 0.34 0.08 Fish meal — — 0.24 0.06 *¹Crudeprotein content (calculated as a dry matter) 14.8%

TABLE 2 Dry period formula feed Rumen-bypass amino acid supply feedProtein supply feed Amount Dairy cow intake Amount Dairy cow intake of adry (Lbs/day), of a dry (Lbs/day), matter calculated as mattercalculated as (%) a dry matter (%) a dry matter Soybean cake 2.81 1.505.81 3.00 (Crude protein 49%) Grass silage 32.13 17.50 31.78 17.00By-pass fat 2.80 1.50 2.80 1.50 Corn fermen- 15.01 8.00 1.87 1.00 tationcake Corn 18.78 10.00 22.08 11.80 Barly 18.78 10.00 23.36 12.50 Vitamin•3.32 1.77 5.61 3.00 mineral Hay (Alfalfa) 5.64 3.00 2.80 1.50 By-passamino 0.74 0.40 — — acid Meat meal with — — 1.87 1.00 bone Blood meal —— 1.31 0.70 Fish meal — — 0.93 0.50 *¹Crude protein content (calculatedas a dry matter) 18.6%

TABLE 3 A B D Feed Small intest- C Excess amino ine absorp- Amino acidamount, RPAA acid tion amount demand supply g/day g/day g/day (%)Methionine 29.5 22.2 15.7 169 Lysine 84.1 88.7 40.0 174 Arginine 72.660.1 45.3 151 Threonine 50.3 49.5 30.0 185 Leucine 97.9 77.8 48.0 157Isoleucine 74.0 51.9 29.4 178 Valine 29.9 58.5 34.3 171 Histidine 53.824.1 15.6 155 Phenylalanine 83.8 50.0 27.1 194 Tryptophan 18.0 11.3 7.4153

TABLE 4 A B D Feed Small intest- C Excess amino ine absorp- Amino acidamount, acid tion amount demand (B/C) g/day g/day g/day (%) Methionine30.2 23.0 15.7 147 Lysine 89.1 62.8 40.0 157 Arginine 78.1 63.9 45.3 141Threonine 62.2 51.6 30.0 172 Leucine 100.8 81.1 48.0 169 Isoleucine 66.253.8 29.4 183 Valine 76.4 61.4 34.3 179 Histidine 31.7 26.2 15.6 168Phenylalanine 66.3 52.6 27.1 194 Tryptophan 16.2 11.3 7.4 NA

TABLE 5 A B D Feed Small intest- C Excess amount, amino ine absorp-Amino acid RPAA admini- acid tion amount demand stration area g/dayg/day g/day (%) Methionine 88.8 52.0 58.3 110 Lysine 186.8 150.3 178.8110 Arginine 177.2 150.0 106.2 143 Threonine 142.2 119.6 100.5 118Leucine 259.9 216.7 183.3 118 Isoleucine 152.5 125.7 142.9 110 Valine182.2 149.5 140.2 113 Histidine 75.8 83.6 81.7 115 Phenylalanine 159.8130.3 102.0 128 Tryptophan 32.0 22.6 35.8 NA

TABLE 6 A B D Feed Small intest- C Excess amino ine absorp- Amino acidamount, acid tion amount demand (B/C) g/day g/day g/day (%) Methionine72.2 59.5 58.3 102 Lysine 234.0 198.5 178.8 111 Arginine 211.7 190.1106.2 179 Threonine 160.6 139.7 100.5 139 Leucine 289.3 247.5 183.3 135Isoleucine 167.6 141.5 142.9 99 Valine 206.9 174.1 140.4 124 Histidine94.1 107.8 81.7 132 Phenylalanine 183.2 155.0 102.0 152 Tryptophan 34.424.3 35.8 NA

TABLE 7 Dry matter intake (DMI) in a feed in Tables 14 and 15 (Kg/day)before calving after calving 3 weeks 2 weeks 1 week 2 weeks 4 weeks 6weeks 8 weeks Protein supply area 13.1 10.4 9.0 14.3 17.0 17.4 17.0Rumen-bypass 12.9 10.2 8.4 13.3 16.1 21.2 21.0 Amino acid administrationarea Holstein cows (15 head/area); secundipara or multipara, amount ofmilk produced −10,000 kg/head/year, feed amount - 24 kg (calculated as adry matter)

TABLE 8 Body condition score (BCS) of dairy cows bred before calvingafter calving 3 weeks 2 weeks 1 week 2 weeks 4 weeks 6 weeks 8 weeksProtein supply 4.1 4.0 3.8 3.2 2.5 2.2 2.5 area Rumen-bypass 4.0 4.0 4.03.4 2.8 2.6 2.5 Amino acid administration area

TABLE 9 Blood glucose value Blood urea nitrogen (BUN) value (mg/dl)(mg/dl) Protein Protein supply area RPAA supply area supply area RPAAsupply area Day 14 before calving 51 52 13.2 11.3 Day 15 after calving36 47 12 2  9.1 Day 56 after calving 49 70 13.5 12.6

Example 2

Forty Holstein secundipara or multipara cows were divided into twogroups, and subjected to a test. The dry period complete mixed feedshown in Table 10 was administered to 20 cows in the control area and 20cows in the rumen-bypass amino acid administration area (RPAAadministration area) from 3 weeks before calving to the calving day.Further, the rumen-bypass amino acid obtained in Production Example 2was administered to the cows from 3 days before the scheduled calvingday. After calving, the lactation period complete mixed feed shown inTable 11 (the amino acid composition is shown in Tables 12 and 13) wassupplied to the control area and the rumen-bypass amino acidadministration area. In the RPAA administration area, it wascontinuously administered for 8 weeks after calving. With respect to thetotal of 40 cows in both areas, the number of days of the first estrusafter calving, the non-conception rate, and the number of matings untilthe conception are shown in Tables 14 to 16. The control area wascompared with the rumen-bypass amino acid administration area. As aresult, regarding the number of days of estrus after calving, the rateof the first estrus which was reached within 100 days was 78% in thecontrol area, whereas it was 89% in the RPAA administration area.Regarding the number of matings until the conception, the rate ofconception by one mating was 33% and the rate of conception by three ormore matings was 39% in the control area. Meanwhile, the rate ofconception by one mating was 55%, and all of dairy cows were conceivedby at most two matings in the RPAA administration area. Thus, theconception occurred at good efficiency. Accordingly, the rate of thenon-conception was naturally decreased. On the other hand, in the RPAAadministration area as compared to the control area, the rate ofnon-conception within 80 days was 55% relative to 22%, and that within120 days was 100% relative to 58%; it was thus improved. It ispresumably because the RPAA administration improved the energy balanceand activated the liver function of dairy cows, maintaining the goodconditions of dairy cows, increasing their bodily strength, andreleasing the stress.

TABLE 10 Dry period Intake of dairy cows Dry matter composition completeformula feed (Lbs/day) (%) Corn silage 7:00 29:4  High-water-contentcorn 4:50 18:9  Beer cake 1:84 7:7 Soybean flour 49 (m) 1:03 4:3 Corngluten meal (m) 0:10 0:4 Safflower meal (m) 0:06 0:3 Wheat flour (m)0:19 0:8 Mineral•vitamin 0:67 2:8 Grass silage 934 7:20 30:2  Cornfermentation cake 0:47 2:0 Blood meal (m) 0:68 2:8 Feather meal blend(m) 0:06 0:3 Urea (m) 0:03 0:1 Total (m) 28:83  100:0 

TABLE 11 RPAA Control area administration area Dry matter Mixing Drymatter Mixing intake ratio intake ratio Lactation period feed (Lbs/day)(%) (Lbs/day) (%) Wheat flour (m) 4:45 7:8 4:45 7:7 Soybean cake (m)3:38 5:9 3:38 5:8 Cane molasses 0:23 0:4 0:23 0:4 Mineral•vitamin 1:612:8 1:61 2:8 Corn silage 40% 12:31  21:6  12:31  21:3  Dry corn flour 6813:93  24:5  13:93  24:1  Corn dist 4:80 8:4 4:80 8:3 Corn gluten meal0:68 1:2 0:68 1:2 Blood meal 0:88 1:6 0:88 1:6 Hardened tallow 0:30 0:50:30 0:5 Safflower meal 3:81 6:7 3:81 6:8 Alfalfa hay 7:63 13:4  7:6313:2  Feather flour 1:40 2:6 1:40 2:4 Bone with meal 9:36 0:6 0:36 0:6Fat 1:11 2:0 1:11 1:9 RPAA — — 0:98 1:7 Total 58:88  100:9  57:88 100:0 

TABLE 12 Lactation period feed amino acid balance (control area) A B D(B/C) Feed Small intestine C Supply amount absorption amount Demandratio (g/day) (g/day) (g/day) (%) Methionine  70:1  58:5  64:5 87 Lysine224:4 188:9 198:5 95 Arginine 230:1 201:6 112:5 179 Threonine 170:1147:3 109:8 134 Leucine 333:5 290:0 204:9 142 Isoleucine 174:1 148:3180:2 93 Valine 236:5 202:3 158:2 130 Histidine 100:5  87:8  68:7 128Phenylalanine 198:8 167:8 112:4 148 Tryptophan  28:5  20:1  39:8 —

TABLE 13 Lactation period feed amino acid balance (control area) A B D(B/C) Feed Small intestine C Supply amount absorption amount Demandratio (g/day) (g/day) (g/day) (%) Methionine  82:7  59:2  65:0 105Lysine 285:1 229:9 199:9 115 Arginine 228:7 201:3 119:7 177 Threonine169:7 147:0 110:8 133 Leucine 333:2 290:0 206:2 141 Isoleucine 173:6148:3 161:1 92 Valine 236:1 202:1 157:2 129 Histidine 100:4  87:7  68:2127 Phenylalanine 198:4 167:4 113:3 148 Tryptophan  28:2  19:9  40:1 —

TABLE 14 Total rate of estrus which was reached after calving (%) withinwithin within 100 days 60 days 80 days 100 days or more Control area 4768 78 100 RPAA administration area 47 68 89 100

TABLE 15 Total rate of mating success (%) Ist 2nd 3rd 4th RPAAadministration area 33 41 68 100 Control area 55 100 — —

TABLE 16 Total rate of non-conception after calving (%) within withinwithin within 80 days 100 days 120 days 160 days Control area 78 67 55 0RPAA administration area 45 18 0 —

Effects of the Invention

Lysine and methionine which are limiting amino acids of dairy cows areadministered to dairy cows to decrease the BUN value that has an adverseeffect on the conception rate and to increase the blood glucose requiredto improve the energy balance, that alanine and glutamine areadministered to dairy cows to increase the blood glucose and to improvethe liver function, and that the use of these amino acids is effectivefor keeping good conditions of dairy cows, allowing earlier arrival ofinitial estrus without any stress, improving the mating conception rateand decreasing the non-conception rate.

What is claimed is:
 1. A method of increasing fertility in high-levellactation dairy cows, which method comprises controlling the dailycontinuous administration of a feed additive in the cows' diet; saidfeed additive being selected from the group consisting of arumen-protected mixture of lysine, glutamine and alanine; arumen-protected mixture of lysine and glutamine; and a rumen-protectedmixture of lysine and alanine; wherein the daily continuousadministration of the feed additive begins approximately 3 days beforecalving and ends approximately 84 days after calving; wherein theincrease in fertility is manifested as a member selected from the groupconsisting of an increase in conception rate; a decrease innon-conception rate; and an early arrival of initial estrus as comparedto high-level lactation dairy cows which do not receive therumen-protected feed additive; and wherein the energy balance of thecows is always plus and the amino acid demand of the cows is satisfied.2. A method according to claim 1 wherein the feed additive furthercomprises methionine.
 3. A method according to claim 1 wherein theincrease in fertility is manifested as an increase in conception rate.4. A method according to claim 1 wherein the increase in fertility ismanifested as a decrease in non-conception rate.
 5. A method accordingto claim 1 wherein the increase in fertility is manifested as an earlyarrival of initial estrus as compared to high-level lactation dairy cowswhich do not receive the rumen-protected feed additive.
 6. A methodaccording to claim 1 wherein during said administration period of thefeed additive the BUN value of the cow is decreased and the bloodglucose of the cow is increased relative to a cow which does not receivethe feed additive.
 7. A method of increasing fertility in high-levellactation dairy cows, which method comprises controlling the dailycontinuous administration of a feed additive in the cows' diet; saidfeed additive being selected from the group consisting of arumen-protected mixture of lysine, glutamine and alanine; arumen-protected mixture of lysine and glutamine; and a rumen-protectedmixture of lysine and alanine; wherein the daily continuousadministration of the feed additive begins approximately 21 day beforecalving and ends approximately 84 days after calving; wherein theincrease in fertility is manifested as a member selected from the groupconsisting of an increase in conception rate; a decrease innon-conception rate; and an early arrival of initial estrus as comparedto high-level lactation dairy cows which do not receive therumen-protected feed additive; and wherein the energy balance of thecows is always plus and the amino acid demand of the cows is satisfied.8. A method according to claim 7 wherein the feed additive furthercomprises methionine.
 9. A method according to claim 7 wherein theincrease in fertility is manifested as an increase in conception rate.10. A method according to claim 7 wherein the increase in fertility ismanifested as a decrease in non-conception rate.
 11. A method accordingto claim 7 wherein the increase in fertility is manifested as an earlyarrival of initial estrus as compared to high-level lactation dairy cowswhich do not receive the rumen-protected feed additive.
 12. A methodaccording to claim 7 wherein during said administration period of thefeed additive the BUN value of the cow is decreased and the bloodglucose of the cow is increased relative to a cow which does not receivethe feed additive.